Core making apparatus



7, 1956 c. w. DANIEL ET AL 2,757,424

CORE MAKING APPARATUS Filed May 20, 1952 3 Sheets-Sheet 1 Fig.1

65 BE E56 66 INVENTORS'.

CLARENCE w. DANIEL By JOHN v. DAVIS ATTORNEY A 7, 1956 c. w. DANIEL ET AL 2,757,424

CORE MAKING APPARATUS 3 Sheets-Sheet 2 Filed May 20, 1952 INVENTOR3. CLARENCE w. DANIEL BY JOHN v. DI!

ATTORNEY 7, 1956 c. w. DANIEL ET AL 2,757,424

CORE MAKING APPARATUS Filed May 20, 1952 3 Sheets-Sheet 3 INVENTORS. CLARENCE W. DANIEL JOHN V. DAVIS ATTORNEY United States 2,757,424 CORE MAKING APPARATUS Clarence W. Daniel and John V. Davis, assignors to United States Pipe and a corporation of New Jersey Birmingham, Ala, Foundry Company,

This invention relates generally to core making apparatus, and particularly to apparatus for making annular cores for forming the bell in centrifugally cast bell-ended pipe.

Cores for this purpose are important factors influencing the quality of the pipe and the percentage of rejects thereof in any pipe manufacturing plant. Prime requisites for such cores are that they shall possess the proper density and hardness to withstand the handling incidental to their use as well as the erosive action of the molten metal thereon. It is particularly important that the socket portion of the core in its green condition be dense and strong enough to permit the application of a blacking coating thereto.

In the apparatus of the present invention annular cores for the above purpose, having the desired density and hardness and possessing a high degree of core-to-core uniformity, are made by first blowing the core sand into a core mold with air under high pressure and thereafter squeezing the sand while still in the mold to consolidate the core.

It is an object of the invention to provide apparatus for making cores of such soundness, density and hardness that they may be handled in the green condition and brush-coated with blacking without appreciable loss due to breakage.

Another object of the invention is to provide apparatus for the above purpose which aifords rapid production of cores of a high degree of uniformity.

A further object is to provide, in combination with a sand blower and mold, apparatus for compacting to the desired density the sand blown into the mold, which apparatus includes a piston defining one end of the mold.

An additional object is to provide a combined blowing and compacting apparatus of the above description wherein the piston carries a plurality of ports for the egress of air used in blowing the sand into the mold.

A still further object is to provide a combined blowing and compacting apparatus of the above description which includes a bin for sand located centrally of the core mold, the bin being so constructed and related to the mold that it forms a part thereof and also functions as a cylinder wall for the compacting piston.

Other and ancillary objects and advantages of the invention will become apparent from the following specification in which reference is made to the accompanying drawings illustrating a preferred embodiment of the invention.

In the drawings,

Fig. 1 is an elevation view, somewhat diagrammatic and partly in section, showing the entire blowing and squeezing assembly together with appurtenances for laterally moving the assembly and for raising and lowering the mold;

Fig. 2 is avertical sectional view taken on the line 2-2 of Fig. 1, looking in the direction of the arrows;

Fig. 3 is a vertical sectional view of the blowing and ice squeezing assembly, with a mold shown in its proper posi= tion to receive core sand from the sand bin;

Fig. 4 is a selective cross-sectional view taken on the line 4=-4 of Fig. 3, looking in the direction of the arrows;

Fig. 5 is a diagrammatic view showing attachment of the air lines to the squeezing apparatus, and the valve for controlling the flow of air to and from the apparatus;

Fig. 6 is a plan view of one of the baflled vents; and

Fig. 7 is a cross-sectional view of a bafi'led vent taken along line 7-7 of Fig. 6, looking in the direction of the arrows.

For a preliminary general description of the core mak ing apparatus of the invention in conjunction wifll conventional appurtenant apparatus with which it is adapted to be used, reference is made particularly to Figs. 1 and 2 where the numeral 8 refers generally to a core blowing and squeezing assembly surmounted by a conical chute 9 provided with opposed flanges 10 and 11, the latter having aperture 12 therein (Fig. 3) for the passage of an air connection to the squeezing apparatus as will appear hereinafter. The flange 10 is secured by means of a plurality of bolts 13 to a carriage 14 comprising a flanged plate 15 which carries wheels 16 adapted for rolling engagement with rails 17 supported by suitable standards 18.

The carriage is moved on the rails 17 by means of a piston (not shown) operating in a cylinder 19 and having a piston rod 2h connected to a yoke 21 secured to one end of the carriage 14. The cylinder 19 is secured to the standards adjacent one end of the rails 17 and is connected to suitable lines 22, 23 which may act alternately as fluid feed and exhaust lines. The lines 22, 23 are controlled by a suitable valve (not shown) which may be contained in a central control station 24.

Positioned above but contiguous to the plate 15 are a hopper 2t? for sand or other comminuted refractory material, having an open bottom as shown, and an air pressure fitting '26 connected by a conduit 2'7 with a reservoir (not shown) of high pressure air. The plate 15 is movable beneath the hopper 25 and the fitting 26 and is provided with an opening 28 which is adapted to register alternately with the hopper 25 when filling the sand bin of the core making machine, and with the air pressure fitting 26 when blowing the core. It will be seen by inspection that the plate 15 acts as a damper which automatically closes the hopper 25 when the apparatus 8 is moved out of alignment therewith, as shown in Fig. l. A quick opening valve (not shown) in the conduit 27 regulates the flow of air to the air pressure fitting 26.

Situated beneath the apparatus 8 and in alignment with the air pressure fitting 26 is a fluid operated jack 29 for raising and lowering a split outer mold member 39 into and out of operative position with respect to the core making apparatus 8. A support and closure plate Eliia is preferably interposed between the jack 29 and mold member 34). A hose 31 which may serve in known manner alternately as a pressure and exhaust line is provided for operating the jack 29. A conventional control valve (not shown) to operate the jack 29 may be positioned in the central control station 24.

Referring now particularly to Figs. 3 and 4 for a more detailed description of the apparatus of the invention, it will be seen that the structural center thereof comprises a sand bin 32 defined by the chute 9, an upper cylindrical wall 33, a lower conical portion 34 and a bottom 35 The conical portion 34 is adapted to nest within the outer mold portion 30 and define therewith a mold 36 having an annular space or chamber 37 which determines the contour of the annular sand core made in the apparatus. The wall 33, which may be considered an extension of the lower conical portion 34 projecting axially from the mold 36, need not necessarily be cylindrical but, if desired, may be of any constant cross-section. However, the cylindrical form illustrated will usually be the most convenient form therefor.- Adjacent the bottom of the bin 32 are a plurality of radial apertures 38 through which sand or other comminuted refractory material may be blown into the annular space 37, as will be de scribed more fully hereinafter.

Surrounding the cylindrical portion of the bin 32 adjacent its upper end is a closed annular piston chamber or cylinder 39 containing an annular piston to from whichdepends an annular plunger 41 projecting below the cylinder 39. The plunger 41 is adapted to enter the annular space 37 at the upper end of the mold 36 for the purpose of compressing the sand in the mold in accordance. with a prime objective of the invention. The inner wall of the annular cylinder 39 is defined by the cylindrical wall 33 at the upper end of which is a radial flange 42 forming a closure for the upper end of the cylinder 39. The outer wall of the annular cylinder 39 is defined by a cylindrical wall 43 depending from the lower face of the flange 42 and attached thereto by means of a plurality of circumferentially spaced bolts 44, or other convenient detachable securing means. These same bolts 44 are used to secure the lower flange ll of the chute 9 to the top of the bin 32.

An annular plate 45 is carried by the cylindrical wall 43 and fixed thereto by an annular weld 46. As shown in Fig. 3, the smaller diameter of annular plate 45 is considerably larger than the outer diameter of the wall 33, thereby providing an annular space therebetween for the passage of the plunger 41. Air or other fluid is introduced into the annular cylinder 39 above the piston 40 by means of a port 47 in the flange 42, which registers with the aperture 12 previously described, into which may be threaded a nipple 48, or other means for attachment of a fluid supply and exhaust line 49. Fluid for actuating the piston 40 may also be introduced into or removed from the cylinder 39 from its opposite end (below the piston 40) through a second supply and exhaust line 58 connected to a nipple 51 threaded into an opening 52 formed in the annular plate 45.

A cylindrical wall 53, having opposed outwardly disposed flanges 54 and 55 is fixed to the lower face of the annular plate 45 by means of a plurality of circumferentially spaced bolts 56. A second annular plate 57 is attached in similar manner to the lower face of the flange 55 by means of circumferentially spaced bolts 58. An annular space 59 is thereby defined into which exhaust alr from the mold 36 is discharged during a core blowing step, as will be described more fully hereinafter. As was the case with the annular plate 45, the smaller diameter of the annular plate 57 is considerably larger than the outer diameter of the Wall 33, providing an annular space therebetween permitting passage of the annular plunger 41 of the piston 41). The cylindrical wall 53 is provided with an opening 60 for the discharge of exhaust air from the annular space 59, and also to provide a point of entry for the line 50 to its connection with the nipple 51.

The annular plate 57 carries at its underside, by means of a plurality of circumferentially spaced bolts 61, a guide and retaining ring 62 of generally frusto-conical form, the ring 62 being used to align and hold together the halves of the split outer mold member 30 and to guide such outer mold member into proper operative position, i. e., concentrically surrounding the wall 34 of the sand bin. Compressed air which enters the mold chamber 37 with the sand escapes to the atmosphere through a plurality of circumferentially spaced baffled vents 63 near the periphery of the outer member 30 of the mold 36, and through similar vents 64 arranged around the bottom of the plunger 41. The baffies for these vents, in the form which we prefer, consist of plugs 65 of metal having a plurality of narrow parallel slits 66 cut therethrough of such width as to prevent the passage of sand but freely permit egress of the air.

Piston 40 is suitably recessed adjacent its greater and smaller diameters to receive the horizontal portions of annular cup leathers 67 and 68 which are held tightly against the top of the piston by means of a retaining ring 69 secured to the piston by a plurality of circumferentially spaced bolts 70. A third annular cup leather 71 is similarly secured to the underside of the piston 40, adjacent its greater diameter, by means of a retaining ring 72 held in position against the piston by the same bolts 70. A fourth annular cup leather 73, with its vertical portion extending upwardly and contiguous with the plunger 41, is held in position against the underside of annular plate 45 by means of a retaining ring 74 fixed to the plate 45 by a plurality of circumferentially spaced bolts 75. The retaining rings 69 and 72 respectively carry flanges 76, 76 and 77, 77 which exceed the height of the respective cup leathers and act as stops to limit travel of the piston 40 in the cylinder 39.

It will be apparent that the stroke of the piston 40 may be varied as desired by replacing one or both retaining rings 69 and 72 with other retaining rings having flanges 76 and 77 of proper height for the piston stroke desired. In Fig. 3, the compression stroke of the plunger 41, as determined by the flanges 77, 77, is represented by the broken line 78.

Reference is now made briefly to Fig. 5 where there is shown diagrammatically a control valve 79 for operating the piston 44) in its cylinder 39. The valve 79, which may be located in the central control box 24, is provided with a cock portion 88 having two independent bores 81 and 82 therethrough, the bores respectively connecting pairs of ports on the surface of the cock which are situated at 90 intervals thereon. In the valve body are corresponding ports 83, 84, 85 and 86, port 84 being connected through a line 87 to a source of air at high pressure, and port 86 being connected to exhaust line 88. Ports 83 and 85 are connected respectively to lines 49 and 50.

In operation, the bin 32 is supplied with sandfrom the hopper 25, after which the entire assembly 8 is moved laterally so as to be in alignment with the air pressure fitting 26. The split outer mold member 30, resting on a support and closure plate 30a, is then raised into operative position within the retaining ring 62 by means of the jack 29 and is maintained in that position until a core is formed and ready to be extracted. At the commencement of the core forming operation the piston 40 is in its uppermost position with the stops (flanges) 76, 76 in contact with the closure 42. in this position, the plunger 41 is of course also in its raised position with its vents 64 communicating with the atmosphere through the opening 64) in the cylindrical wall 53.

Air under high pressure is now caused to enter the bin 32 from the air pressure fitting 26, which air permeates the sand and causes it to flow rapidly into the mold space 37, filling all parts thereof. The air entering the space 37 escapes to the atmosphere through baffled vents 63 and 64. The 4-way valve 79 is now operated to connect the air pressure line 87 to the line 49 and the exhaust line 88 to the line 50, thus causing the plunger 41 to compress the sand in the annular space 37. The 4-way valve 79 is then operated to reverse the pressure and exhaust connections to the lines 49 and 50 to raise the piston 40 to its starting position. Jack 29 may now be lowered, bringing with it the split outer mold portion 30 and the newly formed core. The mold is opened simply by separating the halves, thereby releasing the core.

It will be understood that the invention is not intended to be limited to the specific embodiment described herein, but that various changes and modifications thereof may be made without departing from the spirit and scope of the invention as defined by the appended claims.

What we desire'to claim is:

1. Core making apparatus comprising a core mold having inner and outer walls arranged, in the operative position of the mold, concentrically in nested relation forming an annular mold amber therebetween for the reception of comminuted refractory core material, a plate carrying one of said mold walls and movable to carry said one wall axially into and out of nested relation with the other mold wall, the plate closing one end of the mold chamber in the operative position of the mold, an annular plunger closing the other end of the mold chamber, a plurality of baffled ports in said plunger providing communication between said chamber and the atmosphere for egress of air from said chamber, and means for moving said plunger in the mold chamber toward and away from said plate.

2. The combination with core blowing apparatus of the type having an annular mold the inner wall of which is defined by an apertured wall of a sand bin from which sand is blown radially outwardly into said mold by air pressure in said bin, of an imperforate extension of said bin wall of constant cross-section projecting axially from said mold, a piston surrounding said extension for sliding engagement therewith, an annular cylinder for said piston, said extension forming the inner wall of said cylinder, said piston carrying an annular plunger projecting beyond said cylinder and movable under the action of said piston to extend a limited distance into one end of said mold and to be withdrawn therefrom, and means for moving said piston in either direction in said cylinder.

3. The apparatus in accordance with claim 2 wherein the end of said plunger adapted to extend into said mold is provided with a plurality of baflied ports providing communication between said mold and the atmosphere to afford egress for air in said mold.

4. In core making apparatus for making annular cores by blowing core sand into a mold and thereafter compressing said sand while in the mold, the combination comprising an outer mold member, a sand bin one end of which is nested concentrically in said outer mold member and forming therewith an annular mold chamber for forming said core, the outer surface of said end of said bin having a conformation corresponding to the inner surface of the core to be formed in said mold, said end of said bin being provided with a plurality of openings for introducing sand into said annular mold chamber, said bin having an extension of constant cross-section projecting axially toward its opposite end, a piston surrounding said extension for sliding engagement therewith, an annular cylinder for said piston, said extension forming the inner wall of said cylinder, said piston carrying an annular plunger projecting beyond said cylinder and movable under the action of said piston to extend a limited distance into one end of said mold and to be withdrawn therefrom, and means for moving said piston in either direction in said cylinder.

5. The apparatus in accordance with claim 4 wherein the end of said plunger adapted to extend into said mold is provided with a plurality of bafiled ports providing communication between said mold chamber and the at mosphere to afford egress for air in said mold.

6. The combination with core blowing apparatus of the type having an annular mold the inner wall of which is defined by apertured wall of a sand bin from which sand is blown radially outwardly into said mold by air pressure in said bin, of an imperforate extension of said bin wall of constant cross-section projecting axially from said mold, an annular plunger surrounding said extension for sliding engagement therewith, said plunger forming a closure for one end of said annular mold, and means for moving said plunger axially a limited distance into said end of said mold, the end of said plunger adapted to enter said mold being provided with a plurality of baflled ports providing communication between said mold and the atmosphere to afford egress for air in said mold.

7. Core making apparatus comprising a core mold having inner and outer walls arranged, in the operative position of the mold, concentrically in nested relation forming an annular mold chamber therebetween for the reception of comminuted refractory core material, a support member for said outer wall movable to carry said outer wall axially into and out of nested relation with said inner wall, said support member being adapted to close one end of said mold chamber in the operative position of the mold, an annular plunger closing the other end of said mold chamber, said plunger surrounding said inner wall and being guidedly movable thereon in an axial direction, a plurality of bafiied ports in said outer Wall providing communication between said chamber and the atmosphere for egress of air from said chamber, and means for moving said plunger in said mold chamber toward and away-from said support.

References Cited in the file of this patent UNITED STATES PATENTS 716,870 Crecelius Dec. 30, 1902 1,573,436 Anderson Feb. 16, 1926 1,695,855 Moore et a1. Dec. 18, 1928 1,710,523 Vial et a1 Apr. 23, 1929 2,107,814 Billand Feb. 8, 1938 2,588,669 Taccone Mar. 11, 1952 2,613,409 Miller et al Oct. 14, 1952 

